silicon and fuel

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Posts: 485
Joined: Mon Jul 19, 2004 2:26 pm
Location: Port Elizabeth

silicon and fuel

Post by whisper » Mon Jan 25, 2016 9:50 am

When installing the fuel level sender unit in one of IFH's lower tanks recently I elected to use red RTV type silicon as a sealant on the gasket. BIG MISTAKE :twisted:

When screwing in one of the mounting screws a small "sausage" of silicon fell into the tank. This then morphed into something many times the size and finally lodged itself in the fuel transfer pump.

A small piece also made its way into the main tank. Fortunately that has a finger filter at the outlet so the engine was never starved of fuel.

Lessons learnt
1) Never use a silicon based sealant anywhere near fuel....ever!
2) Use finger filters at all tank outlets (even ferry tanks)
3) Install a filter on the line between the ferry tank and main tank

Pics show the difference in size between the same blob of silicon before and after being immersed in fuel.
wet.jpg (603.82 KiB) Viewed 4790 times
dry.jpg (210.78 KiB) Viewed 4790 times

Johan Nortje
Posts: 82
Joined: Sun Jan 16, 2005 10:12 am

Re: silicon and fuel

Post by Johan Nortje » Sun Jan 31, 2016 8:20 pm

The same happened to me in 2006 when I use silicone to seal the sensor on the main tank. In my case the result was an engin out while still close to the airfield. I could glide back and land safely. After inspection the silicone block the fuel filter.

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